Browse by Archive
ScholarsArchive at Oregon State University
|
In this dissertation I explore the application of two novel modeling
techniques for improving risk analysis of vector-borne disease and discuss their
potential use in integrating environmental risk assessment that guides
environmental and public...
2003-03-06 (iso8601)
|
|
Despite their inherent importance and utility as ecological examples, island
species are among the most endangered and least studied groups. Guam
Micronesian Kingfishers (Halcyon cinnamomina cinnamomina) exemplify the
plight of insular biota as a...
2002-03-12 (iso8601)
|
|
The endemic avifauna of Guam and the Mariana Islands represent a unique
assemblage of bird species found nowhere else in the world and thus, are of
considerable biological and conservation importance. Unfortunately, most of these
species are...
2003-03-18 (iso8601)
|
|
Environmental factors such as chemical contamination can have
immunomodulatory effects on the immune response of fish and may be contributing to
the decline in salmonid populations by augmenting disease susceptibility. Xenobiotics
can interfere...
2001-08-23 (iso8601)
|
|
Marine ecosystems can be exposed to natural and anthropogenic disturbances
that can lead to ecological failures. Marine reserves have been lately suggested to
protect marine populations and communities that have been affected by habitat...
2001-12-20 (iso8601)
|
|
Seasonally, in 1998 and 1999, I examined spatial and temporal variation in
fish assemblages of agricultural, forested, and acid mine drainage tributaries within
the Wayne National Forest (WNF) in southern Ohio. Land use and natural
disturbance...
2001-07-24 (iso8601)
|
|
From 1998-2000, laboratory studies were conducted to examine factors
that impact saltwater-entry behavior and saltwater preference (SWP) of juvenile
chinook salmon, Oncorhynchus tshawytscha. These factors included bacterial
kidney disease, stress...
2002-04-09 (iso8601)
|
|
Large burrowing owl (Aihene cunicularia) populations exist in areas of
intensive agriculture in California, and pesticide exposure has been identified as a
potential threat to population persistence. I evaluated breeding season use of
agricultural...
2002-04-22 (iso8601)
|
|
The composition and distribution of fish assemblages was examined in a
floodplain lake system in the Amazon basin. Quantitative samples were
collected during the 1992-1993 flooding season at Marchantaria Island, Solimoes
River. A total of 25,819...
2000-05-25 (iso8601)
|
|
Co-management is considered an alternative approach to fisheries management,
however, not all co-managed fisheries have been successful. Most studies discussing the
success and failure of co-management have emphasized economic and social...
2001-01-12 (iso8601)
|
|
A series of experiments with Aeromonas salmonicida and infectious
hematopoietic necrosis virus (IHNV) were carried out to determine dynamics of the
spread of infection in chinook salmon (1.2-1.98g) and rainbow trout (1.2-3.1g). It was
found in...
2001-01-08 (iso8601)
|
|
Spring chinook salmon, Oncorhynchus tshawytscha, in the Snake River Basin
are listed as endangered under the Endangered Species Act. The typical life history of spring
chinook salmon is semelparous. An experiment was performed to see if mature...
2002-04-16 (iso8601)
|
|
Processes of metamorphosis, settlement, and growth were examined in Pacific sanddab
using field studies and otolith microstructure. This flatfish transforms at large sizes, has a
gradual metamorphosis, and settles to a nursery on the middle...
2000-08-02 (iso8601)
|
|
Pacific lampreys (Lampetra tridentata) have declined in abundance in the
Columbia River Basin. Although, the reasons for the decline are unclear, we suggest that
development of hydroelectric dams and habitat alterations in tributaries as the main...
2001-01-19 (iso8601)
|
|
We recovered passive integrated transponder (PIT) tags from nine piscivorous waterbird colonies in the Columbia River basin to evaluate avian predation on Endangered Species Act (ESA)-listed salmonid Oncorhynchus spp. populations during 2007–2010....
2012 (iso8601)
|
|
Spawning salmon create patches of disturbance through redd digging which can reduce macroinvertebrate abundance and biomass in spawning habitat. We asked whether displaced invertebrates use non-spawning habitats as refugia in streams. Our study...
2012-06-20 (iso8601)
|
|
Sex steroids, follicle stimulating hormone (FSH),
luteinizing hormone (LH) and gonadotropin releasing hormone
(GnRH) were measured in monosex and mixed sex populations of
rainbow trout during early development. Steroids declined
following...
2000-11-30 (iso8601)
|
|
Freshwater wetlands in the Sacramento Valley provide breeding, wintering,
foraging and stopover habitat for migratory and resident birds. With a loss of 95% of
historic freshwater wetlands, the restoration of wetlands on private land could...
2001-03-14 (iso8601)
|
|
Early ocean residence is considered a critical period for juvenile salmon although specific survival mechanisms are often unidentified and may vary by species or life stage. Columbia River spring-run Chinook salmon Oncorhynchus tshawytscha...
2012-04-25 (iso8601)
|
|
I radio-tagged 191 Hatch-Year (HY) and After-Hatch-Year (AHY) female northern pintails (Anas acuta) in the San Joaquin Valley (SJV), California and studied their movements, habitat use and survival during August March, 1991-94.
Overall, 94.3%...
1999-11-19 (iso8601)
|
|
The Quotient Method (QM) is used by the United States Environmental Protection Agency (USEPA) in ecological risk assessments of pesticides for nontarget organisms. The QM requires several assumptions regarding exposure and hazards of pesticides to...
2000-01-14 (iso8601)
|
|
In the summers of 1998 and 1999, aquatic invertebrate and plant communities were
sampled from nineteen springs in the Warner Basin of southeastern Oregon. Across
the landscape, these springs exhibited a broad range in water temperature (5-24°C),...
2000-10-23 (iso8601)
|
|
Sex differentiation in fish is a labile process that allows sex inversion in several species. The inherent capacity of fish germ cells to differentiate into oocytes or spermatocytes constitutes a key factor allowing for functional sex inversion....
2001-01-12 (iso8601)
|
|
Effects of spray-dried algae, Schizochytrium sp. and Haematococcus pluvialis, on
growth and survival of Manila clam, Tapes philippinarum, spat were determined. Results
of the present study showed that these two different spray-dried diets...
2001-03-14 (iso8601)
|
